feat: NOT_READY after provider shutdown (#216)

Signed-off-by: Todd Baert <[email protected]>

specification.json

@@ -443,6 +443,13 @@
             "RFC 2119 keyword": "MAY",
             "children": []
         },
+        {
+            "id": "Requirement 2.5.2",
+            "machine_id": "requirement_2_5_2",
+            "content": "After a provider's shutdown function has terminated successfully, the provider's state MUST revert to its uninitialized state.",
+            "RFC 2119 keyword": "MUST",
+            "children": []
+        },
         {
             "id": "Requirement 2.6.1",
             "machine_id": "requirement_2_6_1",

specification/sections/02-providers.md

@@ -203,12 +203,15 @@ title: Provider State
 stateDiagram-v2
     direction LR
     [*] --> NOT_READY
-    NOT_READY --> READY
+    NOT_READY --> READY:initialize
     READY --> ERROR
     ERROR --> READY
     READY --> STALE
     STALE --> READY
     STALE --> ERROR
+    READY --> NOT_READY:shutdown
+    STALE --> NOT_READY:shutdown
+    ERROR --> NOT_READY:shutdown
 ```
 
 see [provider status](../types.md#provider-status)
@@ -250,6 +253,15 @@ class MyProvider implements Provider, AutoDisposable {
   }
 ```
 
+#### Requirement 2.5.2
+
+> After a provider's shutdown function has terminated successfully, the provider's state **MUST** revert to its uninitialized state.
+
+If a provider requires initialization, once it's shut down, it must transition to its initial `NOT_READY` state. Some providers may allow reinitialization from this state.
+Providers not requiring initialization are assumed to be ready at all times.
+
+see: [initialization](#24-initialization)
+
 ### 2.6. Provider context reconciliation
 
 [![experimental](https://img.shields.io/static/v1?label=Status&message=experimental&color=orange)](https://github.com/open-feature/spec/tree/main/specification#experimental)